Using Raspbian GUI with default user pi might be not fun, but if you decided to create new user, you might have missed setting up polkit configuration to have new user in administrative authentication dialog. Here's my first Raspberry Pi guide to fix it.

In case you are running e-mail server with Postfix, here is configuration improvement to use stronger SSL and TLS ciphers when connecting to secure SMTP as suggested by Switzerland-based secure mail provider ProtonMail. […]